Middle and late stage lung cancer refers to lung cancer combined with lymph node metastasis in certain areas, such as hilar lymph node metastasis or mediastinal lymph node metastasis. Advanced stage lung cancer refers to the combination of distant metastasis, such as brain metastasis, bone metastasis, liver metastasis, etc. or the appearance of pleural effusion, which is also considered as advanced stage lung cancer. In other words, lung cancer in the middle to late stage is still confined to the chest cavity, but distant metastasis that exceeds the chest cavity is considered advanced lung cancer. The prognosis of intermediate and advanced stage lung cancer is better than that of advanced stage patients, and the 5-year survival rate of intermediate and advanced stage lung cancer is about 30%, while the 5-year survival rate of advanced stage lung cancer is less than 10%. Therefore, delineating different stages of lung cancer is beneficial to judge the prognosis and also to guide the treatment. Middle and late stage mainly involves synchronous radiotherapy and chemotherapy, while advanced lung cancer mainly involves palliative treatment and symptomatic treatment.